ALLENTOWN, Pa. (AP) — Federal environmental regulators signaled Thursday they want to increase oversight of the natural gas extraction industry, announcing they will develop national standards for the disposal of polluted wastewaters generated by a drilling technique known as hydraulic fracturing, or fracking.

Energy companies have dramatically expanded the use of fracking in recent years, injecting millions of gallons of water, sand and chemical additives to unlock gas in deep shale formations in Pennsylvania, Texas and other states. Its prevalence has raised concerns about the potential impact on water quality and quantity.

The Environmental Protection Agency announced that it will draft standards for fracking wastewater — the briny, chemical-laced water that comes back out of the well — that drillers would have to meet before sending it to treatment plants. The industry in recent months has been recycling much of the wastewater or injecting it deep underground, but some of it is sent to plants that are ill-equipped to remove the contaminants.

The new standards would also apply to wastewater produced by coalbed methane drilling, the agency said.

"We can protect the health of American families and communities at the same time we ensure access to all of the important resources that make up our energy economy. The American people expect and deserve nothing less," said EPA Administrator Lisa P. Jackson.

The EPA has largely left it to the states to regulate fracking operations, and environmental groups cheered Thursday's announcement as a long-overdue first step. The agency is also in the midst of a national study of whether fracking has polluted groundwater and drinking water and its potential future impacts.

"The nation is in the midst of a fracking-fueled gas rush which is generating toxic wastewater faster than treatment plants can handle it," Earthjustice attorney Deborah Goldberg said. "The EPA's proposal is a common sense solution for this growing public health problem and will help keep poisons out of our rivers, streams, and drinking water."

Industry groups and Republican lawmakers said wastewater disposal is already regulated by the states, and criticized the EPA for overreach.

"The EPA's announcement is a solution in search of a problem," said Rep. Tim Murphy, R-Pa., co-chairman of the House Natural Gas Caucus.

In Pennsylvania, the administration of Gov. Tom Corbett asked drillers this year to stop sending millions of barrels of salty, polluted wastewater to treatment plants that only partially remove the contaminants before discharging the water into rivers. The practice has stopped, the state's environmental secretary, Michael Krancer, wrote in a July 26 letter to Jackson.

But Krancer also asked EPA to update its standards for wastewater treatment facilities under federal jurisdiction to include guidelines for dissolved solids and bromides, both of which are present in flowback water from gas wells and can damage streams and rivers.

Drilling companies began flocking to the state several years ago to exploit the Marcellus Shale formation, the nation's largest-known reservoir of natural gas.

"Pennsylvania's natural gas developers, as well as its regulators and service companies, are far ahead of EPA's review of wastewater treatment standards for shale gas," said Lou D'Amico of the Pennsylvania Independent Oil & Gas Association.